 But he's recording actually, because I think he's recording, we are recording now, thank you for the reminder. Okay, good, I'll just go on. Okay, so what I'm trying to do with my work is try to understand what are the new physiological mechanisms underlying our capacity of preceding time. So okay, so and I'll just work with all these nice faces here, so I have the, this is basically the work I lead at CISA and all together we are really trying to understand, we're interested in understanding where, how and when time information in a range that spans from a few hundreds of milliseconds to a few seconds is processed in the human brain. So what are the mechanisms that are leading to duration perception. And we try to answer this very overarching, very general question by using the full palette of human neuroscience techniques. So we go from an electroencephalography, functional magnetic resonance imaging, human psychophysics, transplanar magnetic stimulation, and the combination of brain stimulation with neuroimaging techniques. But I'm telling you this, I'm telling you about my work because basically the whole course will try to be really a journey into the cognitive neuroscience and the cognitive neuroscience of time, of temporal cognition and its link with the neuroscience of spatial cognition and numerical cognition. And basically by really focusing on a specific theme of research, I will try really to tell you what is, what is the way we do research in cognitive neuroscience. What are the questions we try to answer, how we zoom in from a very general question understanding the mind to very specific and narrow questions and how we do that through different using different techniques. What is the logic behind our experiments? How do we interpret the data? How then we reach the level of modeling our data and give an interpretation of this data? So I will basically will start so by providing an introduction of time. So I will mainly talk about time. So what is the time I'm talking about? I will start with a few specifications that relates to the subject of the of the lectures. So how do we study duration perception and processing? What are the properties of duration perception? And then this basically I will hopefully I will cover it today. And then in the whole rest of the course, I will really try to answer those two very broad question, which are how and where temporal information is represented in the human brain. And these questions will be answered by giving you empirical evidences that are in favor and against specific theoretical models that have been built to explain how the brain processes and perceive time. So for each of these models that you hear listed here, so the internal clouds, they depended energy, readout, ramping models, three other big frequency models, I will bring empirical evidences against and in favor. Just and then, you know, just to have an idea of really the state of the art in this field, which is a young field in the cognitive neuroscience. And we will I will tell you very soon why is a young. So what is time? Is it someone brave enough to tell me what is time? According to you. Otherwise, yeah, tell me a coordinate. Sorry, a coordinate just like space. Sorry, I didn't get your question. Coordinate is the way of coordinating things. This is what is just like space. It's a coordinate. Like maybe you mean something that it's a reference that we all need to coordinate our lives. This is time. Interesting. Yeah. Different between two response to the brain. Say it again. I'm sorry. I don't know why it's the audio. Wow. The difference between response to the difference between two response to the brain. For example, when you see something and see another one, the different response go to the brain. And this is the time, I think. So it's a sort of a mechanism that that warns you whether there is a mismatch between something expecting something that it's not. This is what you meant. Yeah, I think so. If I'm not mistaken, I say time is the property of a system that possibly allows for configuration. Yeah, that's a reference that we need. Okay, that's it. Time is, oh, sorry. So Gaia, go ahead. Yeah. So I assume that what we perceive as time is the change that happens in the environment that we observe. So this change, for example, if the material, our environment change in some way, we perceive that as time. Okay. Okay. So interesting. So you all said something interesting. So some of you basically mentioned this reference system that helps us to organize our lives. Or this last observation is interesting and you will see will be crucial. It's a change. Time is a change. So we perceive time when there is a change in the environment that surrounds us. And that's really has something that is grounded. But I will tell you what St. Agustin said about the time. He said something similar like this, what is time? If no one asks me, I know what it is. If I wish to explain it to him who asks, I don't know. And I like this quote because it really has two key elements that concerns time. The one is time for a neuroscientist. The first is basically the, so time is obvious is there, right? So while I'm talking, you are sensing. You don't need to watch, to look at your watch, to be able to tell how much time has elapsed since I stopped talking, right? You sense this flow of time. So it's really obvious. It's in what we experience in everyday life. But on the other hand, if we have to really provide, try to study time. So try to give, to explain what it is, it comes, here comes the problem. And we will, you will see why it's problematic also for a neuroscientist to tell, to tell time. So it's obvious, right? So now you will hear two sounds and you have to tell me which one was, so which one was longer? Was the second or the first? Second. Second. Yes. Second. So you see, everybody's able to tell time, right? So it's pretty obvious that the second sound was longer. And so for a neuroscientist, the fact that you were able to tell me that the second sound was longer, that's what matters for me. I don't care if time exists outside of me being able to tell time. So that's, I'm not a physicist, I'm not a philosopher, I'm a neuroscientist. So for me, so it's important the fact that you can experience, you can perceive, you can sense the passage of time. And if you can sense the passage of time, if you can perceive, there must be something in the brain that allows you to do so. So that's the object of, of my work. So try to understand what is this mechanism in the brain that enables you to tell that the second sound was longer, okay? So this is first, you know, first point just to be clear. So and just to keep going with this specification. So you sense the time clearly when you are at the bus stop, right? So the bus is late, you don't need to look at your watch again to feel that you're, so you have some expectations, these expectations are not matched to just rephrase one of your colleagues. And that means that the time has elapsed and the bus is late. And this is, again, a subjective experience of time. Another example is when you are at the streetlight, right? So the light is red, you don't know for how long it has been red. But the longer the red light stays on, the higher is the probability that this red light will turn green. So even in this case, you have a perception of time. So you feel the time and you use this information to make a prediction. So to basically predict that after a certain amount of, a certain amount of time, the green change should happen in the streetlight. But there are other situations in everyday life where your brain needs to process or produce time and you are not aware of. So that happens so without your perception, but they are more implicit. And this happens, for example, when you move. When you play, this is another example that I make and it's very, I think, very effective. So when you play tennis, there are two types of information you bring into process. One, it's information that needs to be processed. One, it's information that needs to be, a time that needs to be produced. And the process is basically the time of the travel of the ball from one side to the other of the court. How long would it take for the ball to be at a reachable distance for me to eat the ball? And the second information is when have to eat the ball. So when is the right time to eat the ball and not miss it? So you see there is a perceptual. So there is something that the brain needs to extract, the temporal information of the moving ball. The second is a timed action to eat the ball. And this happens without perception, so without awareness. So the brain needs this information and it processes without perception. So, and the range, also, okay, another specification. So we are talking about perception of time. We are talking about processing of time without awareness. Okay, so those two things. Second specification is the time scale. When I talk about time, you know, the range is very wide, right? Here I just, I put too extreme, but I mean, this is just for today. I mean, your time spans from microseconds. You know, this is the time your brain needs to process when you have to localize sound in space. When, for example, there is a sound coming from the right, okay, the right hand side. So what happens in there is a place in the brainstem where there are cells that are sensitive to very small delays. So microsecond delays between basically delays of the time of the arrival of the information in the brain. So because the information comes very first on the, comes through the right here and then through the left here because there is the head in between. And so there are areas, there is a piece in the brainstem where there are cells that are sensitive to microsecond delays of the information. On the other extreme here, I put another famous biological clock, which is basically the circadian clock, which I guess most of you have heard of, right? So that's a clock that's, that it's in the, in another area of our brain, in the hypothalamus, in the nucleus supraciasmaticus. In this basically, this is a, this piece of the brain is important to synchronize a lot of physiological events in your body with the alternation of the light and darkness. So lots of fluctuations in your body temperature, fluctuations in the hormonal level. In your sleep awake cycles, they're all synchronized with the alternation of light and darkness. And this clock in the brains, in the hypothalamus helps to do so. And the molecular mechanisms of this circadian clock has been widely studied. In fact, I think two years ago, the Nobel Prize for medicine was, was won by two scientists that studied the molecular mechanism of this circadian clock. But we are not interested neither in microsecond nor in circadian. We are interested in this range of duration that spans from a few hundreds of milliseconds to a few seconds. Okay, which is basically the range of time we need for conscious experience of time. So for perception of duration, but also for all this series of everyday life activity that we carry on without being aware of the time information required, like walking, dancing. And here again, a summary of what I meant. So we are interested in it because the mechanisms that are behind this capacity of telling time in this range are not very well known. Excuse me. Yeah. Can I ask something? Yeah. Hello, Professor. So I was interested, given all this, is there any correlation between maybe let's say, characteristic times of the decay of the activation of certain neural populations within the brain through which the brain can kind of tell time? Yeah. I mean, this is one of the models. In fact, we will see later. So there are models that assume that they're biologically very plausible. So they believe that every piece of the brain can tell time because the dynamics between the neural activity in the brain, between networks, between populations of neurons happens over time. So there are time constants in the brain. There are like processes that happens over time, like short-term synaptic plasticity, long-term potentiations, right? And so the brain can use these processes that happens over time to tell time indeed. And this is correct. Yeah. Do you think those models have any merit? Number one and number two, if you think that's true, are we in any way able to determine where these mechanisms are in the brain or maybe better to phrase my question, are there any particular areas within the brain within which these, let's say, neuronal subpopulations can be found? Yeah. Go ahead. Sorry. No, that's my question. I don't even know if my question necessarily makes sense. So I'm asking you whether it does. It makes a lot of sense. And you would be able to answer this question at the end. I hope you would be able to answer this question at the end of the course, because that's my goal. It's to tell you what we know. And what we know, it's precisely what we are trying to figure it out, is where in the brain these nearer populations are. And through which mechanism this perception or processing of time, it's possible. So the whole course will try to answer this question. So of course, the answer is no answer yet. You should expect that because we're still working on it. But we do have pieces. So we do understand certain things. We know that there are certain brain areas where it's more likely that these populations are. OK, but you have to be patient to have an answer to these questions. But another important specification that concerns time is also the world time. Ma'am. Ma'am. Yeah. So yeah. Sure. Just a question out of curiosity. Ma'am, are there any demerits or merits if we go out of synchronization with our biological clock? Sorry? The duration? Are there any merits or demerits if we go out of synchronization with our biological clock? So if we have, if there are some... So I didn't get the question. Sorry. If there are... We are in sync with our biological clock. With the... Yes. OK. Sorry, Matteo. You have to translate for me. Well, this is a super interesting question. We don't know yet. But because scientists work this way. So first they try to just work in one direction and try to find out everything about something specific. So there are either the people who work in circadian with circadian clocks, biological clocks, and others that, like me, who work on and try to understand what are the mechanisms that enables you to perceive duration. But the interactions between the two are not known. But it's interesting, right? In order to do that, you should run one experiment of the sort of experiment I run when I ask participants to discriminate the duration of a sound, for example, and carry out the experiment, for example, in different day times, right? This is also will be interesting to see whether even the state, the physiological state that depends on your circadian clock influences duration perception. But I don't have an answer to that. OK, another... Yeah. There is something else. I think tomorrow I should wear my earphones. My earphones, maybe I hear better. I had a slight curiosity. So the time we perceive is we consciously perceive time, right? Or is it not, it is unconsciously, I mean, how do we perceive time? It's consciously perceived, right? Yeah, at the point where... So are you like trying to find out where the consciousness reside in our brain? This is the question everybody wants to answer. So where is consciousness? Well, that's also a super difficult question to answer for which no one has a very clear answer. How to study consciousness, right? And whether consciousness, it's perception. This is also a good question. So because if I'm conscious, I perceive time. If I'm not, I cannot. But this does not mean that I'm not processing time. My brain is not processing time. So in a way, studying, you're asking whether studying time would be also a way, as a study, all sorts of perception is a way of studying consciousness. But there are, there is something that seemed to go beyond, so that beyond perception, something that is really defines, it's also sort of a metacognition. So me being able to think about myself, about my cognition, if this is also being conscious. And there are, also there is all sorts of research they try to address, whether there is a part of the brain that is sufficient to be conscious or not. But we still don't know. It's a very complicated question. But there are people who address also that. But in a way it is, studying perception is a way to studying the conscious experience we have of the world. Although perception is something that also animals so that have, and we don't know whether animals have self-consciousness, for example. That's an interesting, they can perceive, because we know that they can perceive, because they can be trained to discriminate. They can distinguish between sounds of different durations, for example. But you know, is this enough to be conscious? Perception, that's another question. A very philosophical, I know neuroscience it is like this. It's a bit of the edge of all these philosophical questions. We try to really see whether there is a quantitative and a biological ground of that. Okay, so but to go back to our subject, so again to the specification. So time means many, many different things, right? So processing information over time. So whatever we process, whatever enters our sensory systems unfolds over time. And the information is processed over time. An interesting question that concerns time, for example, is how does the brain integrates information over time? So I'll give you also another example of, if you are at a concert hall, right? And you see the image of the violinist, okay? And then you hear the sound of the violin. So those two pieces of information reaches the brain at different time, okay? So the information reaches very quickly the auditory cortex, which is specialized to process information that comes from here. And a bit more slowly in your visual system, so the system that receives information from your retina, from your eyes. But nevertheless, what you perceive is something unitary, right? It's a unique percept. You have the image and you hear the sound, has simultaneous. But indeed in the brain, these two pieces of information are not simultaneous at all. How does the brain feel this gap between information? It's also an interesting question. It's called temporal binding problem, okay? And this is a way of studying time in the brain, which is not what we will be talking though, okay? It's just for me to help you to understand how wide can be the range of, you know, the problems of time in the brain. Another question would be simultaneity and temporal order, to decide whether two sounds are synchronous or asynchronous. This is also an interesting issue, okay? But you don't need to perceive the duration of the sound to tell so, okay? To tell whether two events are simultaneous or not. This is another piece of line of research, which is not what I'm talking anyway. Then there is another interesting one. When I give talks, normally people tell me about this, mental time travel. So time, it's also our capacity of placing ourselves in time. So you, we are today, but you should remember, you know, how long ago you had your last holiday? How long ago you were at high school? But you can also place yourself in future, right? You can sort of foresee where you will be in a year time. So this capacity, which is also debated whether it is human or not, or even animals can have this type of capacity of placing in the flow of time. It's also a subject of investigation. So there are people who try to understand how do we, how, if there is a mechanism that enables us to place ourselves in time. And this has, of course, us to do a lot with memory, with episodic memory. Okay. Professor, go ahead. Excuse me. This mental time travel, you mean, not just remembering the memories, but remembering what time we had that memory, yeah, the process of, you know, relating that, what time was that memory? Yeah, exactly. Being able to also, yeah, to be, yeah, it's both things, not just when these certain things has happened, but for example, the temporal relationship between the events in your life. Thanks. Sorry, I've got one question. So to perceive time, one person should be conscious, right? And to consider someone to be conscious, the consciousness requires time to, to calculate the events that's happening around us. And this requirement of time gives us the ability to perceive and to, for example, I don't know, maybe remember something or to, I don't know, be able to calculate something. So consciousness in its base, what it shows is that it needs time, right? But when we're talking about a millisecond activities that the brain needs to process and needs to react, that change the concept into some innate reaction that we sort of do when something happens to us. For example, if I throw something at some person, the person doesn't think consciously, the person just reacts instantly, right? So that changes the concept of time when we talk about a millisecond actions. So how do we, how are we going to find the conception of time and by studying the reaction of our body in a millisecond activities? Doesn't that make it even harder for us to, to find the concept of time, rather than, I don't know, studying processes that actually needs calculation and needs time? For us. If you're asking whether it would be much more useful to study how a process unfolds over time than studying how you're able to react in time. Yes, because we perceive when we... But we study both indeed because what I was saying is that there are people who are interested in investigating how the brain processes information over time. And maybe this links to what one of your first colleague, one of your colleague asked at the beginning, we might use this processing of information over time to that time. So there might be a link between what you're saying, you know, so it's just, so the two lines converge somehow. But at the beginning, we studied separately, right? There are people that are just concerned about how long does it take for the temporal dynamics of any sort of processing in the brain to process a speed, to process a color, you know, to see how the information that comes from auditory and visual information integrates over time. So they're interested in these temporal dynamics of the neural systems. But over time, doesn't that make it... And it turned it in activity to some sort of instinct. I mean, I don't... When the ball... When someone throws balls at me, I don't think I just react instinctively. Yeah. So there is no process... I don't know if in brain a processing happens or not, but I assume when something turns from calculating and measuring things to some sort of activity that I just react, the process that the brain needs to do is different. But you need this process. So you are saying that maybe this automatic process, it's not time. This is what you're telling, it's something, it's a reaction. But that's interesting for us. It's an interesting... So if you react and you don't react... So when you hit a ball, you have to react with a high level of temporal precision. If you don't do that, you will miss the ball or you will be eaten by the ball. And so this means that this precise temporal information needs to be processed or needs to be produced. And this for us is an interesting question. So it's a way of studying how the brain processes this temporal information. You see my perspective? Yes, yes. That's interesting. Thank you. Yeah. And so basically, yeah, this is what we cover. So what we are really... We will be talking a lot in these lectures will be the perception of the duration. So when basically we really ask participants to focus on time because we ask to judge the duration of an event, which is a sound or a visual image on the screen. And we are interested in a processing of information that happens so without subjects being aware, like in the sense of reacting when something happens on the screen. And we manipulate the time of when these events happen. So we force the subjects not to focus on time, but to use time without awareness. But these things will be clear and clear when we go on. Thank you. Okay. What do we need time for? And this is just also very introductory. So why do we need this to use to study time in such a way? Right. And an example is language. Okay. If I say she gave her cat food, you understand that this person basically is feeding her cat. But if I say something, she gave her cat food. Then, of course, the meaning has completely changed. So here I'm making a nasty reward on the cooking skills of this person. So basically a little pose has totally changed the meaning of what I was saying. So really the structure, it's the same. It's just the time that conveys meaning in this sense. So that's what I meant when I said that time is also crucial to understand language. Time is important also to appreciate music. I like to make this example, which is more suitable for Italian opera lovers. Okay. So now I will just play a tune and you have to tell me whether you recognize this tune or not. Any clue of what could be? These are basically notes of a very famous tune, but they are played at the wrong time. So this is again to convey the message that if you change the time, you change the mean. So we are, of course, through experience, we learned to appreciate this tune with these notes at a given time. If we change the time of exactly the same note, we change the meaning. So we made this, we are not able to recognize this tune anymore. And this is the tune. So this is the La Donne Immobile, you know, it's taken from the Regoletto, the Giuseppe Viennese. So again, important. So time, it's, so we need time through all this, right? So this is just a summary of a very introductory part of the lecture. So we really, time is really in most of the things we do in everyday life. It's important to dance, it's important to move, it's important to pay attention because, so when you pay attention to something, you pay attention to a certain special position because something is up in there. But something is up in there at a given point in time, and you need to focus your attention over time. Time is important, again, through synchronizing, you know, to integrate information that comes from different senses. It's important to speech. So it could be a window, really, studying time through understanding cognition. And why is it so difficult to study? Why? Yeah. May I ask a question? I don't know, is this question irrelevant or not? But can we define paying attention? Is this is a good defined thing or quantity? What is, what can we, how can we define paying attention? It's a good question, paying attention. So what we do, as I said at the beginning as a neuroscientist, we try to, this very vague concepts, like paying attention, you translate it into a task that the subject performs and then you ask the subject to perform it because you believe that this task requires attention. Like for example, if I show something, so you really zoom in into the question, you ask a very specific question, you show something on the screen, for example, and something that happens on the left. So you ask on the left, on the right side of the screen. And for example, you can flash before showing these images on the left, on the right, you show first an arrow. And you ask participants to, so the arrow tells the participants to focus attention to one side or the other of the screen, for example, right? This is a manipulation. Oh, and you can make an experiment where for 80% of the trial, the queue is informative. So it really tells, really it's informative about the side of the space where the subject has to attend because the subject has to react to that stimulus. He has to, for example, press a key whenever something on the left-hand side happens. And what you do, you record how fast the subject is in seeing this something on the left-hand side and how is different his performance when the queue, it's false. So it gives a false information. So it tells you, oh, paying attention to the left, but something happens on the right-hand side. So, and then you measure, for example, how quickly you react in those two different conditions, right? So when, so you, if you find differences in these two conditions, you can tell that when you are focusing, you're directing your attention on the left-hand side, you're super quick. So in the condition where the queue is informative, when the queue is not informative, then you should be expected to be slower in reacting to the stimulus because your attention has to be basically refocused from one side of the screen to the other. That's a very simple way to answer your question. That's an experiment, a very famous paradigm. It's called TOSNAP paradigm from the person who basically devised this. So that's the way of defining paying attention or studying attention. And studying attention over time, I can just introduce another variable, so the time, when something will flash on the screen, it would, I can, for example, use a uniform distribution of time and say the majority of the time I show something, I flash something on the screen, it will happen 500 milliseconds after the subject stare at the screen. In the tail of this distribution, it will happen either at 200 milliseconds or at one second. And I can measure how quickly the subject reacts to the stimulus when the stimulus happens in the most likely temporal window, which is around, I don't remember, half a second I said, whereas it's going to be much slower if something is going to be flashed on the screen unexpectedly. So either very early or very late in time. That's the way we do things. But again, it would be much clearer. So I see now in the introduction, there are lots of concepts, but you will see how later in the course, because I will present a lot of experiments. So we have the chance to see how we operationalize the concepts, very abstract concepts. And but one thing that I wanted to also emphasize today is why, so we know a lot about the brain and how the brain processes spatial information. So how, for example, you are able to focus your attention on the left rather than on the right hand side. What are the brain responses where something is flashed on the screen and has this orientation, is oriented 45 degrees, 90 degrees. I know how the brain reacts when something moves at a certain speed or has a certain motion direction. But we know very little on how the brain extract temporal information that is embedded in these flashing objects. And why so difficult? Well, I'll just give you now an example of the physiology of the visual system. So this is basically, imagine this is the external world. These are your eyes. Information come through the eyes. And here at the back of your eyes, there are the nervous, so basically neural cells. So there are receptors. This is a zoom of what is here. So the inner part of your eyes, there is this retina. And in the retina, there are all these cells going from the more superficial parts of the retina to the inner part of the retina. This is tissues in the back of our eyes. And here there are cells, there are cones, so roads, cones, different types of neurons. Here is a neuron. This is just for people who are not familiar with. The neurons have different shapes. This is a sort of a prototypical image of a neuron. He has a body. The cell has a body where there are all these dendrites. So this is the bits of the neuron that receives information. Then this is the variation. So then in order to have the neuron, in order to send a signal, needs to change his electrical potential. And then once this potential reaches a given threshold, then a signal is sent through the axon, so the fiber, and reaches the axon terminal, which is basically the output side of the neuron. So the brain is made of all these neurons. And those are receptors, so different layers of the cells. So these are the receptors, these are ganglion, they are called ganglion cells. But here what is important for me to tell you is that those two types of cells, there are cones and roads, these are photoreceptors are called, because they have a specific function, which is the, so they basically translate, they do this translations of the light, they translate the light, so they are sensitive to the light, and they translate this light signal, the light into a basically a neural signal. They do these translations, they are photoreceptors. Now we do have this sort of cells in our different senses, in our inner ears, in our skin, in our tongue, in our nose. We have this type of cells that have this specific function to translate this external information, so the waves and the lights, into an electric signal. Now there is no translation for time. So there is no equivalent of, there are no neurons that are specialized to do the translation of temporal information, so no time receptors in the brain. There is no, and okay, and when basically the information reaches the retina, okay, when the light reaches the retina, and these photoreceptors become active, and there is a signal that propagates through the different layers, so from cones, from roads to cones to ganglion cells, then from ganglion cells you have this optical, optic nerve, okay, so the optic nerve, and there is a specific pathway this information follows to reach the cortex, okay, from the periphery of your nervous system, so from the retina to several steps in the brainstem up to the cortex, okay, so there is a very specific pathway, it's not just random this communication, so and those fibers which are the axon of the ganglion cell that forms the optic nerve crosses here at the optic chiasma, here it reaches some other cells in the brainstem, which is another part of the central nervous system, so here is this part of the brain is called lateral geniculate nucleus, and here from the lateral geniculate nucleus then it goes from to the thalamus, that is another step, another another nodes of this pathway, and from which is in the inner part, let's say, of the also phylogenetical more ancient part of the brain, so the brainstem, the thalamus, and then the cortex, the primary visual cortex, and as you see color coded, one important principle here is that this pathway is very specific, so everything that is presented on the left hand side, okay, reaches your right visual cortex, and something that is up in the your visual field reaches something that is in the lower in the lower part of the visual cortex, and something that it's something that comes from the right visual field, this process on the left of your visual, so there is a on the left side of your visual cortex, so there is a really very specific pathway, now there is no equivalent pathway for time, okay, but as I again say, I said before, so time is experienced through all our senses, because whatever we experience through our touch, to our smell, to our taste, has a temporal component, has a temporal dimension, and this temporal dimension needs to be extracted somewhere in this pathway, now I want, and there is another peculiarity of time, why so difficult also, because time is so, so compared to other features of our sensory world, like color, shape, you know, you immediately get a color of an object, or the shape of an object, you can say whether it's round or square, but in order to tell time, you need time, you need to wait until the offset of the stimulus to be able to tell whether this stimulus was presented for half a second, or a second and a half, so exactly, now I want to show you this by, I want to share, stop share with this, I want to share something different, I want you to travel through the brain, share, yeah can you, can you see the brain here, okay, can I just ask one thing regarding what you said that time can only be extracted through time, yeah, so the problem is, so the problem is that it's a circular definition, is that correct, would that be correct to say, because you have to wait for time to pass, to then be able to say, well time is that thing that just passed, exactly, exactly and this makes it difficult, so when we studied how shape is processed, how your brain is able to tell whether an object is 45 or 90 degrees oriented, okay, you get this information, so you present this object and you immediately can record a brain signal that tells you that the brain reacts to something that is 45 or 90 degrees oriented, okay, that's the sign, it's a signature that this has been processed, okay, but for time to be processed you have to wait until the end of the stimulus, so it's also a change of perspective for a neuroscientist, right, that you really have to devise something to be able to study time, right, you need to imagine that there is a mechanism that enables you maybe to integrate information over time in the first place, right, and then maybe you need to imagine something that reads out the information that has been integrated over time, it's not something discrete, it's very continuous, the passage of time, okay, so, okay, now I want to, that's a brain scan, this is taken with magnetic resonance, you mentioned this is a static image of, that's me, myself, as you, I mean, of course, you don't, you know, that's me with my big nose, you can tell from the profile, okay, and I can, so these are my eyes, you see, so what you saw schematically, this is in my brain, I can navigate through the brain, right, so those are my, so you see, this is the optic nerve, okay, so these are the axons of the ganglion cells that from meretina goes into the chiasma, okay, so the chiasma is, so you see here the fibers from the two eyes cross, is this white, I'll show you, I lost it, echo, this one, you see, this white here, whatever is, so whatever has fat is white, is bright, so the white matter is white, the white matter is made of axons guys, so it's basically the bits of the neurons where the information goes, and it's fat because the fat makes the transmission to be faster, okay, whereas the body cells made the gray matter, so whatever you see now here, dark, it's gray matter, okay, so this is, and basically, so that's the chiasma where the fibers cross, then the information from the chiasma, so optic nerve, chiasma, crossing, then it goes into the brainstem, into this, this is the brain, this has a shape of a heart, this is the brainstem, you see, this is the spinal cord, this is called the pons, this is the, this brainstem, and here there are the superior colliculus, this is the brainstem, again, where the information from the chiasma goes, and then from the chiasma, from the, sorry, from the colliculi, it goes into the talamus, the talamus is more challenging to see, it's something that is around here, okay, so base of the brain, okay, what you see very bright here, this is the corpus callosum, it's basically the major fiber tracts that exist in your brain, and it helps to connect the two hemispheres, okay, I can show you, okay, this is, so you see this is one hemisphere, that's the other, okay, so I'm moving left to right, right, so my, you see, that's, okay, left to right, this is a bellum, beautiful, it's a beautiful image, this is taken at Seven Tesla, so ultra high fields where you have a very, you can reach a very small spatial resolution in the precision, so in these fibers connects the two hemispheres, okay, but that's not important for us today, so the important thing is that from the talamus, which is more or less here, inform me where there are these nucleus genicolatus lateralis, you go into the visual cortex, that's the back of the brain, okay, so, and that's where you, this is the, this is the first, the first note of the, where the information reaches the cortex from the retina, okay, so, and here again it's very, so whatever it's lower in the retina, it's upper, so you see this sulcus, this is called calcarine, it's up, whatever, whatever it's down in, it's like an optic camera, like that is reversed, is mirrored, the world is mirroring the cortex compared to reality, whatever is up is down in the sulcus, so this is very precise, okay, just to, and then information from the visual cortex, the primary visual cortex goes into other steps in order, and then here you extract the basic information of the visual, the visual information like the shape, the orientation, and then the more the, and then from the primary visual cortex you go through other regions that are here, and that are, for example, specialized, here there are areas that are specialized for recognition of certain object categories, like faces, houses, so the more, so the more, there is a sort of visual hierarchy of information processing that goes from processing very basic feature, edges, luminance, to very, very complex object recognition, like, you know, there are certain parts of the brain, you are able to, you know, they're particularly sensitive to faces, for example, you know, there are cells where the populations of cells, they are very sensitive to faces, but not, for example, to object, visual objects that have different properties, like houses, or other type of objects, that not, everything that it's not face. Anyway, I think we are, so tomorrow, I will now stop sharing this and go back, because I think we are, wow, time flies, I have to say, so I have to be less ambitious, I think in, yeah, so then tomorrow, I will tell you what are the tasks that we actually use for studying time, okay, so how do we measure in experiments time, and what type of task we use, what are the variables we measure in order to quantify then the subject performance, okay, then we will start with the models, but I will upload, I will make sure that you will have the files of, there is a detailed syllabus, and I, for those who are interested, for every lecture, have some reference to give, some papers to suggest if you are curious to read. Yes, thank you very much. Hello, may I ask a question? Yeah. I don't know if it's relevant or not, but since we're talking about time, it's more of a history related question. I wanted to know if that the sense of time was there since the beginning or something happened that we felt like, okay, we need something, we need a definition for time. Super interesting question. We don't know, well, one question is ontogenetically, so whether, for example, whether the, the mechanism that we develop to tell time are there since birth, or we develop in our, in our after birth, so through our experience, okay, and the first quest, so the same question can be answered in an ontogenetically point of view. Yeah, this is a good question. We don't know. We know that kids, for example, so one thing is, okay, one thing is the concept of time, and one thing is the processing of time. The processing of time is there since the birth most, you know, we know this more or less. We don't know in much of a detail, and this is something, for example, amongst Sukinon exploring with my research, but we know that, for example, of course, kids are very sensitive to expectations, okay, so if something unexpectedly happens in their visual field, even if their vision, it's not very refined, they can react to it. So a mismatch is something that requires time, okay, so, so like matching an expectation or not to be sensitive to that requires time. So we know that probably in, so certain mechanism that enables your brain to tell time without consciousness are there since birth. Different is the concept of time. The concept of time is something that kids develop, you know, with scholarization, right, so at 10 years they can have a concept of that, so what was yesterday and tomorrow, the concept of time in this sense, a more conceptual way of thinking about time. Ontogenetically, so if we believe, if you are thinking about evolution, how the sense of time has evolved with the species, this is the species, this is an interesting question, because I think how do we tell time indeed? We do through change, there is no way we are able to tell that something, so whatever changes in our environment or whatever changes in what we do can help you to tell time. So this is, again, I don't know, so but I think that this is a capacity that we developed when through a change that is our own change in our own movements, or it's a change of something that is surrounding us, that is in what we see in the environment. Thank you very much. Professor, I have a question. You mentioned earlier about experience and time, so I was just thinking with respect to perception, with respect to time, perception emerges only from experience of time in individuals. That is to say, without any experience or without any experience of an event, there can be no perception. I was wondering how do nuances in experience affect perception? It's a good question, experience effects can affect perception. If there are experiments, of course, we cannot do these things in humans because these are unethical, but you can, for example, force animals to deprive animals from sensory inputs. I was actually wondering from a perspective of experimental design and measurement. So just at the top of my head, I was thinking, so what if there were two people caught in traffic in a red light and these two people are under the same event, but they're on different conditions. Say, for example, one person is sitting calmly and driving, waiting for the red light to be green, and the other is feeling the urge to pee. So for the person that is feeling the urge to pee, it seems that the time is taking. Ages takes ages. Yes, this is also, it has been studied in the lab. So the person that has this urgency, it's focused on time, and the more you focus on time, the more time seems to to dilate. The less attention you pay to time, the less the time is, so the less the time looks shorter. The watch pot never boils. It's the same example. And this intuition that you have, it has been proved in the laboratory. And this can also, its interest, so the observation is replicated. It's true. It could happen, depends on your state and the fact that you're, where your cognition is directed towards time or away from time. And this can also be, again, interested to tell what is the mechanism, because maybe the more energy, the more incoming sensor information I integrate over time, the longer time seemed to be. Maybe we tell time through this. Excuse me? Yeah, that's good sir. Yeah, go ahead. Okay. Okay. What is the smallest time scale in brain? I mean, what is the smallest and effective time scale in brain? There are different time scales in brain from chemical reaction to population activation activities. I didn't know which one is more important. When every temporal window has its own importance, we have several scales. As I said, just to talk about system. Sound space localization happens in the range that requires microsecond precision. Duration, perception, it's hundreds of milliseconds. So every time, there is no, I wouldn't, I wouldn't say there is no fundamental temporal scale. The question is how, maybe how, how fine is your, this we can measure, how fine is your, the resolution of your temporal system. So how small it needs to be the difference between two sounds in duration in order to be perceived as different in duration. And this could be like, this is very subjective. So we do measure discrimination thresholds. And it's something that varies in subject to subject and can be also different in the same subject during the day, according to the physiological state of the person. And for example, in the auditory domain, the difference could be even 10 milliseconds difference to be able to discriminate the duration of two sounds. Do we really need to be conscious for perceiving time? Do we need it to be? Conscious for perceiving time. Yeah. Well, whenever you perceive your conscious, so perception is a conscious experience of something. Okay. So that's by definition. But during, if you are not conscious, you're not doing the sleep. That's an interesting question. What happens of time during sleep? And no one knows. This is a question to be answered with an experiment. Yeah, we don't know. You definitely post. Thanks. The processing of time probably happens. It depends on your physiological state because you might, you are able to tell time. So what I talked, today I talked a lot about the time that is embedded in your sensory stimuli. But if you think deeply, we can sense time even in absence of a physical stimulus. Now, would we tell time in that case? And I think through physiological states and also even neurons, maybe it's really this background noise can be used to tell time. I have a question. Okay. Thanks. Yeah. So even let's say primitive organisms, like single cell organisms, even they have some processes that happen inside their cells. And through their process, we can say that maybe they also have some idea of time. So their idea of time and how we perceive time, how are they connected? Is there like a bridge between something that happens at the cellular level with which these primitive organisms perceive time and the way complex organisms like mammals perceive time? So are you basically asking, so what is the relationship between this? So even tissues can tell time. I will present an experiment on organotypic slices. So really, even a slice of a brain, so you don't need a network to observe the temporal dynamics in the brain tissue. You can do that. You can train the tissue to have an activity that is temporarily precise. But this doesn't really mean perceiving time, you see? So perceiving time means experiencing time in a piece of even very simple organism. There is no way we cannot tell that this very simple organism tells time. There is time in the dynamics of the cells. This we see, we observed and you can do that even in vitro. But experiencing time, you have to measure it somehow. So in animals you can do, we can train rats to discriminate the duration or to make a time movement because this is what we do with experiments. Okay, so I think, well, this is just the first of nine lectures by Domenica. And so I'm sure there's a lot of discussions, a very interesting subject. And so I would review it for today. Thank you very much, guys. And I hope I will present really data and I will show you this data in the next lectures. Yes, yes. So I would close our session for today at this point. And then we will reconvene tomorrow at 2 p.m. Central European time. Thank you all for joining and see you tomorrow. See you.